This invention relates to a rotary fluid displacement apparatus, and more particularly, to a fluid compressor unit of the scroll-type.
Scroll-type apparatus have been well known in the prior art. For example, U.S. Pat. No. 801,182 discloses a device including two scroll members each having an end plate and a spiroidal or involute spiral element. These scroll members are maintain angularly and radially offset so that both spiral elements interfit to make a plurality of line contacts between spiral curved surfaces thereby to seal off and define at least one pair of fluid pockets. The relative orbital motion of the scroll members shifts the line contact along the spiral curved surfaces and, therefore, the fluid pockets changes in volume. The volume of the fluid pockets increases or decreases dependant on the direction of orbital motion. Therefore, the scroll-type fluid displacement apparatus is applicable to compress, expand or pump fluids.
The scroll-type fluid displacement apparatus is suited for use as a refrigerant compressor of an automobile air-conditioner. Generally, it is desirable that the compressor should be compact and light in weight. In particular, the refrigerant compressor for an automobile air conditioner is necessarily compact in size and light in weight because the compressor is placed in the engine compartment of an automobile. However, the refrigerant compressor which is placed in an automobile must be connected to a magnetic clutch to transmit the rotary output of the engine. The weight of the magnetic clutch is therefore added to the weight of the compressor to thereby increase the total weight of compressor unit.